1. Field of the Invention
This invention relates to a protective sleeve for a hypodermic syringe that locks the sleeve over the needle once the syringe has been used for its intended purpose and the syringe is ready to be disposed of. The sleeve reduces the chance of someone being accidentally stuck with the needle and becoming infected.
2. Description of the Related Art
Many inventors have attempted to solve the problem of syringe safety with varying degrees of success.
U.S. Pat. No. 4,932,940 to C. F. Walker, et al., on Jun. 12, 1990 for a Needle Guard Device describes a sleeve on a syringe that traverses a V-shaped slot. The sleeve is spring loaded in a position covering the needle. As the sleeve is pulled back exposing the needle, a pin in the slot enters the other leg of the V and when the sleeve returns to the needle covered position, a set of teeth engage a rachet and lock the sleeve in the needle covered position.
U.S. Pat. No. 4,966,592 to C. A. Burns, et al., on Oct. 30, 1990 for a Protective Sleeve for a Hypodermic Needle shows a sleeve slidingly engaged on a barrel of a syringe and having the sleeve springingly biased toward and extending beyond the distal end of the needle. There is a Y-shaped slot that locks the sleeve in a retracted, operable position.
U.S. Pat. No. 4,998,924 to A. B. Ranford on Mar. 12, 1991 for Double Sleeve Safety Syringe describes two sleeves that interact with a tab that locks the longer sleeve in an extended position enclosing the needle.
U.S. Pat. No. 5,176,656 to W. B. Bayless on Jan. 05, 1993 for an Automatically Positioned Needle Sheath for a Disposable Hypodermic Syringe shows a syringe having two sleeves. The inner sleeve has three movable shields arranged at 120 degrees. Each shield has a tab that when the sleeve is at an extended position past the distal end of the needle, it forms a barrier around the needle. The sleeve must be pulled forcibly back from the distal end of the needle in order to open the shield and expose the end of the needle.
The present invention overcomes many of the shortcomings of the related art.